The invention relates to the art of digital calculators and, more particularly, such a calculator specifically adapted to perform the task to averaging letter grades earned by students in each course during a particular school term to determine the final grade to which the student is entitled. It is an improvement on the analog device described in this inventor's previous United States Pat. No. 3,470,368 issued Sept. 30, 1969.
During a marking period teachers generally administer various test instruments such as quizzes, tests, exams, and assignments such as term papers, reports, essays, laboratory reports, etc. that are assigned letter grades. To obtain an exact grade average the instructor must assign a numerical number to each letter grade, sum these numbers and divide the sum by the total number of letter grades to obtain the average. This must be done for each student.
The previously noted patent describes and generically claims an analog device for performing these operations. While such device has obtained a measure of commerical success, certain drawbacks are inherent from its very nature. Among these are a tendency to drift, particularly when the averaging sequence is not performed quickly, an inability to indicate the number of entries which have been made, limited accuracy to extended decimal places and no provision for "in sequence" corrections. This analog device, moreover, is limited practically to the single use of averaging grades.